Radiodynamic receiving system



Feb. 19 1924': 1,484,605

J. H. HAMMOND, JR

RADIO DYNAMIC RECEIVING SYSTEM Original Filed Aug. 20, 917

Patented Feb. 19, 1924a UNITED S;.TAT'EIS' Joan HAYS ammonia, .13., or eno'ocasrn a, a

P TE T snicnusnrrs.

' 'RADIODYNAHIC .SYSTHE.

Application filed August 20,1917, Serial 1H0. 187,062. Renewed July 7, 1999.

To all'whomz't may concern:

Be it known that 1, JOHN Hers HAM- MOND, Jr., a citizen of the United States, and a resident of Gloucester, in the county of Essex and Commonwealth of Massachusetts, have invented an Improvement 1n Radiodynamic Receiving Systems, of which the following description, in connectionwith the accompanying drawings, is a speclfication, like characters on the drawings representing like parts.

- This invention relates to means for and methods of simplifying the manipulation of radio-dynamic receiving systems that employ beat reception, and is mtended particularly to facilitate the operation of tuning in su systems or in any system employing audible beats.

In order that the principle of the invention may readily be understood I shall set -forth one form of means for practicing the invention and the best mode known to me for carrying the same into efiect.

The drawing represents diagrammatically a portion only of a radio-dynamic receiving system having one type or form of my invention applied thereto.

Referring moreiparticularly to the drawing, I have indicated at 1, 2, terminals of a radio-dynamic receiving system and upon which are impressed in some well-known manner, not herein necessary to more fully describe, the high frequency electrical oscillations with which it is desired to beat. Extending from the terminal 1 are three leads or conductors 3, 4, 5 connected respectively to condensers 6, 7, 8. Said terminals 1, 2 extend to and are rovided with the inductance coil 9, whic is inductively cou led with the coil or winding-10. Leading cm the inductance coil are conductors 11, 12, and from the former extend conductors 13, 14. respectively extending to and connected with condensers 16, 17 18. The conductor 12 extends to and is provided with inductance coil 19.

The condensers 6, 7, 8, the inductance coil 9, the condensers 16, 17, 18, and. the induct-- ance coils 10, 19, form the tuner or transformer which is to be properly resonated with the high frequency impressed upon the terminals 1, 2.

I have indicated at 20 an inductance coil leading from which are conductors 21, 22, and extending therefrom respectively are conductors 23, 24, 2 26, 27, 218, withwbich are operatively associated or connected, as shown, the condensers 29, 30, 31, 32. The

circuit including the said inductance coil 20 and the condensers 29, 30, 31 is the main osclllatlng circuit of an oscillating gaseous detector 31'. The said circuit throughthe inductive coupling between 19, 20, impresses upon the circuit 10, 19, 16, '17 18 a high frequency diflering from the received high frequency by a certain or desired amount.

In said circuit 10, 19, 16, 17, 18, therefore,

there are thus superimposed the two high frequency osci11ations,thus giving rise to the well-known phenomenon of beats, the

beat frequency being determined by the difference between the two high frequencies to which I have referred.

From the inductance coil 19 extends a lead or conductor 33, which is connected to some.

the latter is a conductor 46, 47 extending to the plate 48 of the gaseous detector 35. The conductors 44, 47 extend to, and have connected therewith, the inductance coil 48.

By extending the terminals 11, 33, to the gaseous detector 35, or some other suitable type of detector, and if the circuit 45, 48 is adjusted so that its natural period is that of the beats hereinbefore referred to, the

said circuit 45, 48-will be fed by rectified groups having the frequency of the saidv dilbeats, and hence the said circuit will build up strongly.

I have represented at 49 a coil inductivel coupled with the coil 48, and from whicii lead terminals 50, 51 connected with which iS a condenser 52. The said circuit 49, 52 thus inductively coupled to the circuit 45, 48, may also be resonated to this heat fre quency and the terminals 50, 51 extend from it to any desirable detector, as, for example, a pair of telephones, not herein shown. By providing a pair of telephomes or other means afi'ordin audible rec/eption,'l[ secure advantaw whlc-h are of peculiar .impozc t m n the useof my invention In carrying out my invention I rovide a movable member or means, prefera ly in the form of a switch, and for. the purpose I have herein re resented a switch 53 of the 5 rotary fan-bled; type, and pivotally mounted at 54, it being rotated in any suitable manner. As herein shown, the said switch. is provided with three metallic sectors or blades55, 56, 57, which are insulated from each other and are spaced equiangular-1y. Each of the said blades,-as'the switch is rotated,-. short-circuits the group of contact points 58, 59, 60, 61, 62, 63, 64, 65, 66 of the respective conductors 58", 59, 60, 61, 62, 63264, 65, 66 leading respectively from the condensers 17, '7, 6,

16 and 18. v

The results of such short-circuiting are circuit 6, 7, 8, 9; second, the tuning of the circuit 10, 16, 17, 18; and third, the changing of the frequency of the oscillation generator 31' attached tothe circuit 20, 29, 30, 31. The condensers 6, 7, 8, 16, 17, 18, 29, 30, 31 are preferably so adjusted at the time of as sembling them that as the switch-53 is rotated a point at a time the circuits 6, 7, 8, 9, and 10, 16, 17, 18 remain properly in resonance, and at the same time the frequence of the oscillation generator is maintained dif- 'ferent from thatof the said impressed frequency by a constant amount or, in other words, the beat frequency is to be maintained constant.

This enables the circuits 45, 48, and 49, 52 to remain fixed throughout, and it also results that the telephone or telephones preferably employed subsequent to the circuit 49, 52 may always be maintained at that frequency at which they are the most sensitive, and which in practice may be in the neighborhood of one thousand cycles per second.

In the drawing I have indicated only three adjustments or positions of the rotary switch 53, but it is to be understood that this number may be increased without limit.

The condenser 32 is preferably a variable condenser for the reason that in practice it has been found that an oscillating gaseous detector does not give rise to a frequency determined solely by the constants of its main oscillating circuit. The frequency depends on the filament heating'current and the high voltage applied to a slight extent. The preferably small, variable condenser 32 is introduced mainly for the purpose of aifording fine adjustment to compensate for the vagrancy of the oscillating gaseous detector.

he principle herein disclosed is particularly applicable in a system making use of a complex emitted wave form consisting of a, high fre uency and a secondary fre uency above the imit of audibility by whic signals 'are made through the variation of such secondary frequency and are made audible threefold, namely; first, the tuning of the at the receiving station by beating to such secondary f uenc Since both the high and the secon ary requencies are above audibility in the referred or typical receiving system to whic I have referred, the tuning up of a receiv' system to a transmitting system is ordinarily quite tedious, involving as it does, feeling about or experimentin for two frequencies simultaneously. I pre erably standardize' both the transmitting and the receiving sets during manufacture, the transmitting set being standardized to emit high frequency waves whose frequen- 0105 may be designated by the Figures 1, 2, 3, 4 etc., and whose secondary freqpencies may be designated by the lettersv A, C, D

etc. The receiving station is calibrated to this same high and secondaryv frequencies which are here designated in the same man ner on the switch point.

It will be evident from the foregoing de-- scription that by the disclosed method I greatly simplify the tuning up of a receiving system, and particularly a system makinguse of the com lex emitted wave form consisting of a hig frequency and a secgnldary frequency above the limit of audii ity.

Having thus described one illustrative embodiment of m invention and the best mode known to me or practicing the same, I desire it .to be understood that, although specific terms are employed, they are used in a generic and descriptive sense, and not for purposes of limitation, the scope'of the invention being set forth in the following claims.

Claimse 1. The combination with an oscillatory circuit, of means arranged to simultaneously impress upon said circuit two series of periodic impulses having different frequencies respectively to produce periodic electrical beats in said circuit, means to change the 'tuning of said circuit, and means controlled by said second-mentioned means for varying the frequency of one of said series of impulses and maintaining the frequency of said beats constant.

2. The combination with an oscillatory circuit normally tuned to respond to periodic electrical impulses of a predetermine frequency, of means associated with said circuitfor impressing thereon periodic electrical impulses having a frequency different from saidfirst-mentioned frequency to produce electrical beats in said circult, means for varying the tuning of said circuit, and means controlled by said second-mentioned means for va ing the frequency of the oscillations pro uoed b saidfirst-mentioned means to maintain the frequency of said beats constant.

3. The combination with .an oscillatory clrcuit ncluding a primary tuning element,

eteor of a second oscillatory circuit controlled by said first-mentioned circuit and including a primary tuning element, a secondary tuning element associated with each of said circuits, means also associated with said circuits for impressing upon one of them a local frequency to produce beatsin said circuits, a movable element, and means controlled by said element for causing said rimary tuning elements to act simultaneous y either independently of said secondary tuning elements or in combination with said secondary tunof said onance and to simultaneously change said local frequency in such a manner as to maintain the beat frequency constant.

4. The combination with an oscillatory circuit including a primary tuning element, of a second oscillatory circuit controlled by said first-mentioned circuitand including a primary tuning element, a secondary tuning element associated 'with each of said circuits, means also associated with said circuits for impressing .upon one of them a local frequenc to roduce beats in said circuits, a rotata is e ement, and means controlled by said, element for causing said primary tuning elements to'act simultaneously either 'independently of said secondary tuning elements or in combination with said secondary tuning elements to control the tuning of said circuits and to maintain said circuits inv resonance and to simultaneously change said local frequenc in such a manner as to maintain the beat requency constant. c

5. In a receivi system for electrical oscillations, the coiiiiiination with a receiving circuit tuned to. a given frequency, of a sec ond circuit connected to and controlled by said first mentioned circuit and tuned to said frequency, a local source of energy arranged to produce oscillations of a frequency different from said first mentioned frequency and to act upon one of said circuits to produceelectrical beats therein, and a single. movable element, and means controlled thereby for simultaneously changing the tuning of saidcircuits fromthe said given frequency to another. predetermined frequency and at the same time changing the fre uency of said oscillations produced by sai source to such an extent as'to maintain the frequency of said beats constant.

6. In a receiving system, the combination with an oscillatory clrcuit tuned to a given frequency, of a second oscillatory circuit in! ductively connected to said first mentioned circuit and tunedto the same frequenc a local source of ener arranged to pro ace in one of said circuits oscillations having a frequency difi'erent from said first mentioned frequency and thereby to produce electrical beats, and a rotary element and means controlled thereby whereby u on the rotation of said element the tuning 0 said circuits may besimultaneously changed from mid given frequency selectively to any one of a plurality of other frequencies and at the same. time said rotary element will operate to change the frequency of the oscillations produced by said source and to such an extent as to maintain the frequency of said beats constant.

7. In a receivin system, the combination with a receiving circuit-tuned to a g ven frequency, of a second circuit. inductively connected to said first mentioned circu1t andtuned to the same frequency, a local source of energy arranged to act inductively upon 8 said-second mentioned circuit to produce oscillations therein having a frequency different from said first mentioned frequency whereby electrical beats are produced in said second mentioned circuit, and a movable element and means controlled thereby whereby the frequency to which said circuits are tuned and the frequencv of the oscillations produced by said local source may be changed in such a manner'that the frequency of one of said circuits will always be the samaas the frequency of the other of said circuits,

and the fre uency of said oscillations pro-' duced by sai source will be so changed as to maintain the frequency of said bwts constant. y

a In testimony whereof, l have signed my name to this specification.

JOHN HAYS HAMMOND, an.

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